What is black light? If you turn on a black light bulb in a dark room, what you can see from the bulb is a purplish glow. What you cannot see is the  ultraviolet light that the bulb is also producing. Our eyes can see the visible light in a spectrum ranging from red through orange, yellow, green, blue and violet. Above violet is ultraviolet light, which we cannot see.

What you see glowing under a black light, whether it is a fluorescent poster, something you've painted with fluorescent paint or a newly-washed white T-shirt, is different phosphors. A phosphor, is any substance that emits visible light in response to some sort of radiation. In other words, a phosphor converts the energy in the radiation into visible light.

So a fluorescent paint contains a phosphor that converts UV radiation into a specific color of visible light. Normal colors simply reflect light, but a fluorescent color absorbs the radiation and re-emits it in the visible spectrum, sort of like a light bulb emits light, so it looks much brighter than a normal color.

Black light units and there accompanying tubes/bulbs come in a variety of types and sizes, anywhere from six inches to four feet in length. Most are AC powered, but some of the really small ones are also available in battery powered models.

Fluorescent Black Light Tubes
When most people think of black lights, they think of the fluorescent tube type. These produce much more ultraviolet light than most any other type of bulbs. The most common sizes for black light tubes is eighteen, twenty-four and forty-eight inches in length. When it comes to the amount of ultraviolet light that is generated, size does matter! The larger the bulb, the more black light that is produced. These types of bulbs also use much less power than other types and do not generate anywhere near as much heat, making them much safer to use. These are the best types of black lights for general purpose Halloween glow-in-the-dark lighting effects.

All consumer grade black light units meant for Halloween that we've seen are of the single UV tube design, and generally have a black fixture. Beware of packaged black light units that use proprietary black light tubes. Years ago we purchased two forty-eight inch black light units, unaware that the manufacturer had designed the bulbs only to be used in there light fixtures and that we could only buy their replacement bulbs or fixture when the bulb burned out, became broken or the ballast in the fixture failed. Unfortunately, the manufacturer went out of business, leaving us with two worthless blacklight fixtures.

Fluorescent Black Light Bulbs
Like there much bigger brothers, fluorescent blacklight bulbs produce much more ultraviolet light than incandescent black light bulbs, although not as much as the large tubes do, and generally have a useful range of about six to eight feet. Compact fluorescent black light twist bulbs like the one to the right only use thirteen watts of electricity and have a useful life in the thousands of hours. These types of bulbs will fit in most standard incandescent lamp sockets. These also work great when placed in a metal parabolic housing such as a "Clamp Lamp" when you need to direct the black light to a specific area or decoration.

Black Light Cannons
High powered black light units have been used by movie makers, theme parks, night clubs and special effects professionals for decades. For most people, there high price has kept them out of mainstream Halloween use in the home, but this is changing as the price of these types of units have dropped substantially, now under $200.00. The Chauvet Black Shadow pictured right, is one such example of a high powered 400watt black light cannon that is used by professionals. Its long throw generated ultraviolet light can cover area's up to seventy feet by sixty feet. These units use a special 400watt mercury vapor blacklight bulb to produce this high level of ultraviolet light.

Black Light Flashlight
We've all seen the small battery powered, handheld black light units, but we bet you didn't know that they make UV flashlights that work great for directing black light onto fluorescent Halloween decorations, props, posters or just about anything painted with fluorescent paint. Arachnid™ Blacklight Flashlights are available with 14, 28 or a whopping 49 UV LED's. The Arachnid A49 Ultra Violet 49 LED Flashlight features water-resistant high-strength aluminum case and toggle on-off switch for continuous or hands free use. Fluoresces at distances up to thirty feet in darkness.

Incandescent Black Light Bulbs
You've probably seen the blacklight bulbs that are shaped just like a regular household light bulb, but are a dark purple in color. Usually selling for only a few dollars, these incandescent type black light bulbs are a complete waste of money as an emitter of UV light. They produce an extremely small and mostly unusable amount of ultraviolet light, that is only effective within a few inches from the bulb. They also tend to get very hot, which not only shortens there lifespan, but also increases there potential as a fire hazard. If you should use these bulbs, be sure to let the bulb cool sufficiently before handling it.

LED Black Light Panels
Black light units using arrays of LED's that produce ultraviolet light are the newest entry into the world of black lights. If the cost comes down and they have a long of a life as promised, this may be the wave of black light use for Halloween in the future. The LED Shadow blacklight unit from Chauvet is one such unit. This unit has built in special effects including Blackout/static/dimmer, and can even strobe. Adjustable flash rate, dimmer and static in stand-alone via dipswitches. This unit has provides coverage of twenty feet by twenty feet, and includes brackets for wall and truss mounting. LED's also have a very low power consumption.